Enum Error 

#[non_exhaustive]
pub enum Error {
    Io(Error),
    BadMagic {
        found: u16,
        expected: u16,
    },
    BadChecksum {
        what: &'static str,
    },
    UnsupportedIncompat(u32),
    UnsupportedRoCompat(u32),
    NotFound,
    NotADirectory,
    IsADirectory,
    AlreadyExists,
    DirectoryNotEmpty,
    ReadOnly,
    NameTooLong,
    NoSpaceLeftOnDevice,
    InvalidArgument(&'static str),
    InvalidInode(u32),
    InvalidBlock(u64),
    OutOfBounds,
    CorruptExtentTree(&'static str),
    CorruptDirEntry(&'static str),
    Corrupt(&'static str),
    TooManyLinks,
    Unsupported(&'static str),
    JournalNotReplayed,
    Stale,
}

#[non_exhaustive] (#120): a new way to fail is a new variant, and without this every variant added was a break for any caller matching exhaustively. A match outside this crate needs a _ arm.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Io(Error)

Underlying device I/O failure.

BadMagic

Magic number mismatch — not an ext4 filesystem.

Fields

found: u16

expected: u16

BadChecksum

On-disk structure failed checksum validation.

Fields

what: &'static str

UnsupportedIncompat(u32)

Filesystem uses an INCOMPAT feature we don’t implement.

UnsupportedRoCompat(u32)

Filesystem uses a RO_COMPAT feature we don’t implement (read-only mount required anyway).

NotFound

Path component or inode not found.

NotADirectory

Path resolution hit a non-directory mid-walk.

IsADirectory

Operation refused because the target is a directory and the syscall only operates on regular files (POSIX EISDIR — used by unlink(2), truncate(2), etc).

AlreadyExists

Target already exists (POSIX EEXIST — used by create(2), mkdir(2), rename(2) when no-replace is requested).

DirectoryNotEmpty

Directory must be empty (POSIX ENOTEMPTY — used by rmdir(2), rename(2) replacing a non-empty dir).

ReadOnly

Write attempted on a device opened read-only (POSIX EROFS).

NameTooLong

Path component longer than EXT4_NAME_LEN (255 bytes) — POSIX ENAMETOOLONG.

NoSpaceLeftOnDevice

Container (xattr in-inode region, xattr block, etc.) has no free space for the requested entry — POSIX ENOSPC.

InvalidArgument(&'static str)

Caller passed a malformed argument or attempted a semantically invalid mutation (POSIX EINVAL — e.g. truncate-grow, moving a dir into its own subtree, operating on a legacy non-EXTENTS inode).

InvalidInode(u32)

Inode number is invalid (0, > total inodes, etc.).

InvalidBlock(u64)

Block number is invalid (> total blocks).

OutOfBounds

Read/write past end of file.

CorruptExtentTree(&'static str)

Extent tree structure is corrupt.

CorruptDirEntry(&'static str)

Directory entry corrupt (rec_len out of range, name too long, etc.).

Corrupt(&'static str)

Generic spec-violation error.

TooManyLinks

The inode’s link count has no room for another link (POSIX EMLINK): a file at MAX_LINKS (65000) links, or a directory with that many on a volume without DIR_NLINK.

Unsupported(&'static str)

A structure this driver can read but cannot correctly modify. Distinct from Error::ReadOnly, which is about the mount, and from the Unsupported* feature errors, which are about the volume: this is one operation on one object being refused because doing it would leave the filesystem worse than not doing it.

JournalNotReplayed

A write refused because the volume’s journal holds committed transactions this mount has not yet replayed onto the device: a lazy mount before crate::fs::Filesystem::replay_journal_if_dirty. Writing first would commit over the unreplayed log and lose it. Maps to EROFS: the mount is read-only until the replay runs.

Stale

An inode handle no longer names the file it was taken from (POSIX ESTALE): the inode number is out of range or reserved, the inode has been freed, or it has been freed and reused under a new generation.

Implementations

impl Error

pub fn to_errno(&self) -> i32

Map an error to a POSIX errno suitable for the C ABI / FSKit.

Values are macOS POSIX errno numbers (which match Linux for every code used here — the divergence only starts at ENOTSUP).

Trait Implementations

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<Error> for Error

fn from(e: Error) -> Self

Converts to this type from the input type.